Optical disk apparatus and optical pickup device

Abstract

A temperature sensor is disposed in an optical pickup to detect a temperature of an objective lens. An optical element (for example, a collimator lens) is driven according to a temperature change of the objective lens, which corrects deterioration of an optical characteristic of a laser beam passing through the objective lens. Good recording/reproduction is smoothly performed even if the optical characteristic of the objective lens is changed with the temperature change.

1. An optical disk apparatus comprising:
 an optical pickup device which includes: 
 a laser source, 
 an objective lens which causes a laser beam emitted from the laser source to converge onto an optical disk, 
 a temperature sensor which detects a temperature of the objective lens, 
 an optical element which corrects deterioration of an optical characteristic of the laser beam passing through the objective lens, and 
 a photodetector which receives the laser beam reflected by the optical disk; and 
 a control circuit which drives the optical element based on a detection signal from the temperature sensor, wherein
 the control circuit has a functional portion for defining a correlation between a detection signal of the temperature sensor and a proper drive amount of the optical element, and the control circuit performs drive control of the optical element based on the correlation defined by the functional portion and the detection signal from the temperature sensor, wherein 
 the functional portion retains a reference table in which the detection signal of the temperature sensor and proper drive amount of the optical element are correlated with each other, 
 wherein the functional portion detects the proper drive amount of the optical element based on a detection signal of the photodetector in driving the optical element, the functional portion updates the reference table based on the proper drive amount and the detection signal of the temperature sensor, and 
 the control circuit performs drive control of the optical element based on the updated reference table and the detection signal of the temperature sensor. 
 
 
     
     
       2. The optical disk apparatus according to  claim 1 , wherein the functional portion re-updates the reference table based on the detection signal of the temperature sensor or the detection signal of the photodetector. 
     
     
       3. The optical disk apparatus according to  claim 2 , wherein the functional portion re-updates the reference table, when a change amount of the detection signal of the temperature sensor exceeds a threshold, or when quality of the detection signal of the photodetector is lower than a threshold. 
     
     
       4. The optical disk apparatus according to  claim 2 , wherein, during the re-update, the functional portion detects the proper drive amount of the optical element based on the detection signal of the photodetector when the optical element is driven, and the functional portion re-updates the reference table based on a linear function satisfying both the current proper drive amount and the current detection signal of the temperature sensor and the proper drive amount acquired in the previous update and the detection signal of the temperature sensor acquired in the previous update. 
     
     
       5. An optical disk apparatus comprising:
 an optical pickup device which includes: 
 a laser source, 
 an objective lens which causes a laser beam emitted from the laser source to converge onto an optical disk, 
 a temperature sensor which detects a temperature of the objective lens, 
 an optical element which corrects deterioration of an optical characteristic of the laser beam passing through the objective lens, and 
 a photodetector which receives the laser beam reflected by the optical disk; and 
 a control circuit which drives the optical element based on a detection signal from the temperature sensor, wherein
 the control circuit has a functional portion for defining a correlation between a detection signal of the temperature sensor and a proper drive amount of the optical element, and the control circuit performs drive control of the optical element based on the correlation defined by the functional portion and the detection signal from the temperature sensor, wherein 
 the functional portion retains a reference table in which the detection signal of the temperature sensor and proper drive amount of the optical element are correlated with each other, 
 wherein the functional portion retains a plurality of reference tables corresponding to operation modes, and drive control of the optical element is performed based on the reference table corresponding to actual operation, and 
 the operation modes are defined based on rotation speed of the disk. 
 
 
     
     
       6. An optical disk apparatus comprising:
 an optical pickup device which includes: 
 a laser source, 
 an objective lens which causes a laser beam emitted from the laser source to converge onto an optical disk, 
 a temperature sensor which detects a temperature of the objective lens, 
 an optical element which corrects deterioration of an optical characteristic of the laser beam passing through the objective lens, and 
 a photodetector which receives the laser beam reflected by the optical disk; and 
 a control circuit which drives the optical element based on a detection signal from the temperature sensor, wherein
 the control circuit has a functional portion for defining a correlation between a detection signal of the temperature sensor and a proper drive amount of the optical element, and the control circuit performs drive control of the optical element based on the correlation defined by the functional portion and the detection signal from the temperature sensor, 
 wherein the functional portion sets the proper drive amount of the optical element to the detection signal of the temperature sensor based on a linear function defining a relationship between the detection signal of the temperature sensor and the proper drive amount of the optical element, wherein 
 a plurality of correlation functions corresponding to operation mode are defined in the functional portion, and drive control of the optical element is performed based on the correlation function corresponding to actual operation, and 
 the operation modes are defined based on rotation speed of the disk. 
 
 
     
     
       7. The optical disk apparatus according to  claim 6 , wherein the functional portion retains a gradient of the linear function, the functional portion detects the proper drive amount of the optical element based on the detection signal of the photodetector when the optical element is driven, and the functional portion sets the proper drive amount of the optical element based on the linear function determined by the proper drive amount and the detection signal of the temperature sensor and the gradient. 
     
     
       8. The optical disk apparatus according to  claim 6 , wherein the functional portion updates the linear function based on the detection signal of the temperature sensor or the detection signal of the photodetector. 
     
     
       9. The optical disk apparatus according to  claim 8 , wherein the functional portion updates the linear function, when a change amount of the detection signal of the temperature sensor exceeds a threshold, or when quality of the detection signal of the photodetector is lower than a threshold. 
     
     
       10. The optical disk apparatus according to  claim 8 , wherein, during the update, the functional portion detects the proper drive amount of the optical element based on the detection signal of the photodetector when the optical element is driven, and the functional portion updates the linear function satisfying both the current proper drive amount and the current detection signal of the temperature sensor and the proper drive amount acquired in the previous update and the detection signal of the temperature sensor acquired in the previous update.